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AUX POWER CALCULATIONDATE- 3/09/2015ADITYA ALUMINIUM ,LAPANGA

What is Aux Power

The quantum of Energy consumed by a generating station, expressed as a percentage of the sum of gross energy generated at the generator terminals of all the units of a generating station

It is the total energy produced by a power plant minus the total power put in to the grid from that unit

Aux Power = Gross Power Output Net Power Output

Thus the total saving in Aux Power will directly increase the Net Power Output of the plant

It has two components Unit Auxiliary Power and Station Auxiliary Power

Concentrating to EquipmentsGAP ANALYSIS IN DRAFT SYSTEMREASONS OF VARIANCE IN DRAFT SYSTEMTARGET-Reduction in ID FAN loading from 1686 amp to 1500amp.REASONS OF VARIANCEHigher ash content in coal.Seal leakages in APH.Poor ESP performance.High total air flow.Boiler and ESP duct leakages. Air leakage from bottom ash hopper.High primary air flow in mill due to measurement inaccuracy.ID FAN suction duct design to be as per OEM.

IMPROVEMENT SCOPEHigher ash content in coal. Proper blending of coalSeal leakages in APH. Seal clearance to be inspected and to be adjusted accordingly.Poor ESP performance. Collection efficiency of ESP to be improved by proper setting of the charge ratio and lower FGET.High total air flow. SADC modulation to be ensured in accordance with boiler load for optimum combustion , FLAME PROPAGATION TEST to be carried out.Boiler and ESP duct leakages. O2 measurement to be carried out at ESP inlet &outlet.Air leakage from bottom ash hopper. Already cooling doors are closed, proper sealing of bottom ash system to be done & new opportunities to be explore.High primary air flow in mill due to measurement inaccuracy Calibration of flow and pressure Tx in mill air system to be ensured.GAP ANALYSIS IN PRIMARY AIR FANREASONS OF VARIANCE IN PRIMARY AIR FANTARGET-Reduction in PA FAN loading by 30 amps.REASONS OF VARIANCEHigher ash content in coal.Seal leakages in APH.High primary air flow in mill due to measurement inaccuracy.High primary air DP across APH.High MILL DP .Shifting of operating point of fan.High pressure drop across duct.

IMPROVEMENT SCOPEHigher ash content in coal.-- Proper blending of coalSeal leakages in APH.-- Seal clearance to be inspected and to be adjusted accordingly. High primary air flow in mill due to measurement inaccuracy.High primary air DP across APH.-- Cleanliness of basket to be checked & proper DP measurement across APH to be doneHigh MILL DP . Condition mill internals to be checked properly at regular interval , classifier setting to be done appropriatelyShifting of operating point of fan. Due to detoration of fan performance or change in system resistance.High pressure drop across duct.-- change in system resistance may be due to accumulation of ash in PA DUCT or change in duct design.Three mill operation for 100% TMCR(As 99.1 tph coal is required for 100% TMCR at designed GCV & MILL capacity is 37tph) by proper blending of the coal.MILL brake down due to foreign material ingress to be restricted by proper installation of magnetic separator .Single PA FAN operation with three mills in service14GAP ANALYSIS IN COOLING WATER SYSTEMREASONS OF VARIANCE IN COOLING WATER SYSTEMTARGET- Single CW Pump operation.REASONS OF VARIANCELower vacuum in condenser.Poor pump efficiencyChocking in CW line either in condenser or in nozzle at Cooling Tower.High DP across Condenser.High DP across Debris Filter.

IMPROVEMENT SCOPEFlow Measurement of CW pump to be carried out, for Calculation of Heat and mass Balance of Condenser.

Air leakage into the condenser are needs to be indentified by using Helium Leak detection test or some other Methods to rectify them.

COLTCS to be operated properly at regular interval.

Debris filter Cleaning to be done properly at regular interval.

ACF operation to be done properly at regular interval.

Regular inspection and cleaning of cooling tower Nozzle and fills.

Single CW pump operation to be implemented after arresting air ingress into the condenser.

17GAP ANALYSIS IN COMPRESSED AIR SYSTEMREASONS OF VARIANCE IN COMPRESSED AIR SYSTEMTARGET- Single COMPRESSURE operation.

REASONS OF VARIANCE.

Leakages in compressed air line.Low Compressor efficiency.

IMPROVEMENT SCOPERemote Operation for Compressor to be implemented.

Clean air-inlet filters regularly. Compressor efficiency will be reduced by 2 percent for every 250 mm WC pressure drop across the filter.

Keep compressor valves in good condition by removing and inspecting once every six months. Worn-out Bypass valves can reduce compressor efficiency by as much as 50 percent.

Minimize low-load compressor operation; if air demand is less than 50 percent of compressor capacity, consider change over to a smaller compressor or reduce compressor speed appropriately.

A smaller dedicated compressor can be installed for ignitor Cooling at Boiler, instead of supplying air through lengthy pipelines. And SA to Boiler May be Cut off. And HFO guns may be kept in Healthy conditions.

20.IMPROVEMENT SCOPECompressor free air delivery test (FAD) must be done periodically to check the present operating capacity against its design capacity..Reduce compressor delivery pressure, from 6.8 to 6.2kg/cm2, to save energy.Keep the minimum possible range between load and unload pressure settings.A smaller dedicated compressor can be installed for ignitor Cooling at Boiler, instead of supplying air through lengthy pipelines. And SA to Boiler May be Cut off. And HFO guns may be kept in Healthy conditions.On account of high pressure drop, ball or plug or gate valves are preferable over globe valves in compressed air lines

THANK YOUSIBASIS DASSibasis.das@adityabirla.com8018043669